Fluid switch



E. J. MLLER Sept. 2, 1930.

FLUID SWITCHv Filed June 25. 192B any Patented Sept. 2, 1930 Pnala'rvOFFICE EMILV J. MLLER, F ANDERNACH, GERMANY FLUID SWITCH Application ledJune 23, 1928, Serial No. 87,832, and in Germany-September 16, 1927.

This invention is directed to an improvement in mercuryl switches inwhich the circuitclosing member is in the form of a perforated striparranged between the spaced terminals of the circuits and serving, whenin one position, to admit a body of mercury to electrically connect saidterminals.

The main difliculty in switches of this character is to so arrange themovable member or perforated strip as to prevent accumulation of themercury beneath the same while at the same time permitting the necessarymovement of the strip for switch purposes. Furthermore, as heretoforeproposed, such l5 switches require a comparatively large quantity ofmercury as the entire switch chamber must be filled with mercury toprovide the pro er connection.-

he primary object of the present invention is the provision of meanswhereby the erforated strip or movable switch member 1s so mounted inthe switch construction as to insure such contact with the operatingpartas to prevent mercury leakage beneath the l5 strip, provision beinmade for4 a reserve quantity of mercury a ove the strip.

A further object of the invent `n is the provision of a cut-oil' forbreaking the current connections without the necessity of moving theperforated strip or withdrawing the mercury. y

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is a broken longitudinal section through a switch constructedin accordance with the present invention.

Figure 2 is a transverse section4 of the same showin a slightly modiedconstruction, the cut-cti` being 1n operative position.'

Figure Sis a similar view, the cut-oil being in inoperative position.

The improved-,switch includes a chamberlike construction having a baseplate a which forms the base of the switch and through which conductorterminals b are extended, their ends lying flush with the upper surfaceof the base plate. A guide g overlies the base platea, being arran ed inspaced relation to the latter to vprovi e a narrow passage 0 throughwhich the movable switch member operates. Beyond the base plate, theswitch is formed to provide a depressed channel or chamber to receive asuitable quantity of mercury, indicated atz', and it is to beparticularly noted, as will be evident from the drawings, that thismercury is not in sufficient quantity to normally-reach the narrowassage between the base plate a and the guide, g.

The movable member ofthe switch is in the form of a more or lessfiexible strip d,

which if desired may be endless, and which is adapted to pass aroundrollers e supported from the guide g and arranged in a mercury chamberat the res ective ends of the switch. .This movable mem er or strip isformed with perforations, .indicated at j", and these perforations mayfollow any .regular or desired order; that is to say,'by the arrangementof the perforations, any particular relation of terminals b may beenergized in a particular position of the movable member, as is wellunderstood in switches of this type.

, A n essential and desirable characteristic of switches of this type isthe necessity for preventing the mercury from accumulating between themovable member and base plate, as if this condition is permitted ltoexist, short-circuiting or undesirable switch connections willnecessarily follow. In order to 'provide for this desirable'function,the movable member of the switch, in being led from the upper surface ofthe base 'plate to and around the rollers e passes over the downwardlyinclined wall section a. This wall section a .forms an angular relationwith the surface of the base plate, so that the strip or movable memberis. drawn snugly over the rounded corner or shoulder formed by thejuncture of the base plate and inclined wall a,'thus tendin to maintainthe movable strip in a comparatively tight fit with the upper surface ofthe base plate. i

, The volume of mercury is, normally not suicient to reach the s acebetween the-base plate and guide and w en the switch is dev sired foruse, the level ofthe mercury isdncreased through the medium of a block karvranged in the mercury chamber and adapted kto be depressed manuallyat will. Obviously,

the depression of this block tends to raise the normal level of themercury in the chamber so that it will reach the space between the baseplate a and the guide gand so pass through the perforations f in themovable member to complete the electric connection between the guide gand those terminals b in the base plate with which the perforations f inthe movable member or strip are in register: The mercury chamber has adepending partition p around which the mercury is directed 1n theoperation ofthe block c to prevent current impulses.

To provide a reserve supply of mercury overlying the movable switchmember d, the gulde g is formed With grooves 71. which may extendlongitudinally or transversely, or both, of the guide and open tothespace between the guide and baseplate a. This reserve supply ofmercury insures an accurate filling of the perforations f of the movablestrip in all switch conditions.

To provide for cutting off the switch withoutthe necessity of moving thestrip n?, there is arranged between said strip and the base plate acut-ofi' n formed with perforations o to register, in one position ofthe cut-off, with the terminals of the conductors b extending throughthe base plate. The cut-off n has an accurate sliding fit with the baseplate surface and the movable strip bears snugly upon the upper surfaceof the cut-off as illustrated. Obviously, with the cut-oil' in. positionto register with the terminals, the movable strip d controls thecircuiting arrangements in accordance with positions of the perforationsf in said strip, while with the cut-off moved so that its openings o areout of registry with the terminals of conductors b, the circuit isbroken.

The switch is designed for any and all uses to which sucha switch may beput, it being here shown as controlling the various illuminating membersof a sign c with an energizing source indicated at B, one side of whichis in connection with the guide g.

What I cla-im to be new is:

1. A iuidswitch having a base plate, terminal conductors leading throughthe base plate and terminating flush with the surface thereof, theswitch including a mercury chamber arranged beyond the base plate, a`

guide plate overlying the base plate and forming a "common circuitingterminal, a. perforate strip movable through the space between the guideand base plate, and means for raisingl the level of the mercury atwillin the chamber to and above the space between the base plate and guide.

2. A switch including a base late and a mercury receiving chamber thereeyond, circuiting conductors leading through the base plate, a guideforming a common circuit terminal and arranged in spaced relation to thebase plate, means operative in the space between the guide and baseplate for determining circuiting conditions, the normal volume ofmercury in the chamber being insufficient to reach said space, and meanswhereby the level of the mercury in the chamber may be raised andlowered at will.

3. A switch including a base plate and a mercury receiving chambertherebeyond, circuiting conductors leading through the base plate, aguide forming a common circuit terminal and arranged 1n spaced relationto the base plate, means operatlve 1n the space between the guide andbase plate for determining eircuiting conditions, the normal volume ofmercury in the chamber being insufficient to reach said space, and ablock operative in the chamber to raise and lower the level of themercury at will. l

4. A fluid switch comprising a base plate, a mercury' reservoir belowand beyond said base plate, circuiting conductors leading through saidbase plate, a guide forming a common circuit terminal and arranged inspaced relation to said base plate, means operative in the space betweenthe guide and base plate for determining circuiting conditions, a`circuiting strip adapted to pass thru the reservoir and thence over thebase plate, the normal level of the mercury in the reservoir being iustbelow that of the strlp at the point of passing over the base plate, andmeans for raising the level of the mercury in the reservoir.

In testimony whereof I aix my slgnature.

EMIL J. MLLER.

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